title: Plasmid as a measure of microbial degradation capacity for 2,4-dichlorophenoxyacetic acid.
abstract: The purpose of this research was to pursuit the quantification of microbial degradation capacity for 2,4-dichlorophenoxyacetic acid (2,4-D) by detecting and quantifying a prominent 2,4-D degradation encoding plasmid. Batch reactor acclimation, de-acclimation, and re-acclimation tests were conducted during which periods the courses of 2,4-D dissipation and plasmid evolution were quantitatively measured. Pure cultures of bacterial strains were detected to give rise to a plasmid approximately the size of 90 kb after acclimation. The 90 kb plasmid content of Arthrobacter sp. increased when degradation occurred after acclimation, with a rate that corresponded closely to the degradation rate. During de-acclimation, plasmid content declined exponentially at a half-life of approximately 3.5 days. Re-acclimation saw a renewed induction of plasmid, but substrate consumption limited the rise of plasmid to a level much lower than after the first acclimation. This research recommends a method for measuring the microbial degradation capability for a xenobiotic.
authors.affiliation: Department of Environmental Engineering, Da-Yeh University, Dacun, Changhua, Taiwan, ROC. chong@mail.dyu.edu.tw
authors.forename: Nyuk-Min
authors.initials: NM
authors.lastname: Chong
authors.forename: Hung-Wei
authors.initials: HW
authors.lastname: Chang
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000378:metabolism* / Q000494:pharmacology*; D000222:Adaptation, Physiological / Q000187:drug effects* / Q000235:genetics*; D001420:Bacteria, Aerobic / Q000145:classification / Q000502:physiology*; D001673:Biodegradation, Environmental; D004269:DNA, Bacterial / Q000187:drug effects / Q000235:genetics*; D010957:Plasmids / Q000187:drug effects / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; D015084:2,4-Dichlorophenoxyacetic Acid